Event details

Today's many different nervous systems illustrate a major conundrum in evolutionary theory: do neurons and brains share common descent (homology) or do they derive from independent (homoplasic) origins? The aim of this meeting is to clarify and discuss evidence for homologous brain segments and circuits across phyla, as well as competing evidence for and against independent origins of nervous systems.

Abstracts and biographies of the organisers and speakers are available below. A selection of papers from the meeting will be published in a future issue of Philosophical Transactions B.

Attending this event

This meeting has already taken place. Recorded audio of the presentations can be found below.

Professor Nicholas Strausfeld

Regents Professor, Department of Neuroscience, Division of Neurobiology, University of Arizona

Nicholas Strausfeld received his BSc and PhD from University College London. After postdoctoral research at the University of Frankfurt as an Alexander von Humboldt Fellow he joined the Max-Planck Institute for Biological Cybernetics in Tübingen and from there moved to the European Molecular Biology Laboratory in 1975. He took his habilitation at the University of Frankfurt in 1986 and then moved to the University of Arizona. He received a John Simon Guggenheim Memorial Foundation Fellowship in 1994, a John D. and Catherine T. MacArthur Foundation Fellowship in 1995, an Alexander von Humboldt Senior Research Prize in 2001, and a Volkswagen Stiftung Visiting Professorship in 2009. He was elected a Fellow of the Royal Society of London in 2002. He is presently a Regents' Professor in the Department of Neuroscience and Director of the University of Arizona's Center for Insect Science. He has authored two books: “Atlas of an Insect Brain” (1976) and “Arthropod Brains: Evolution, Functional Elegance, and Historical Significance” (2012).

Dr Frank Hirth, King's College London, UK

Frank Hirth is a senior lecturer and principal investigator at the Institute of Psychiatry, Psychology and Neuroscience (IoPPN) at King's College London. He received his PhD in Zoology at the University of Basel in Switzerland and trained in neurogenetics at the universities of Freiburg, Basel and the MRC National Institute of Medical Research in London. During his time at the Institute of Zoology in Basel, he discovered evolutionary conserved genetic mechanisms underlying pattern formation in the insect and mammalian brain. His current research focuses on neural mechanisms underlying action selection in health and disease, and their evolutionary conservation.

Schedule of talks

The evolution of arthropod nervous systems: insights from a centipede

Professor Michael Akam FRS, University of Cambridge, UK

Abstract

Myriapods (centipedes and millipedes) are now recognised as the sister group to the entire pancrustacean clade (i.e. insects and crustaceans). They therefore represent an important outgroup for comparison with insects and crustaceans, and for inferring the ancestral organisation of the arthropod nervous system. However, very little molecular work has been done on the development of myriapod brains. We have used a centipede, Strigamia maritima, as a model for studying the molecular embryology of myriapod development. The genome sequence of this centipede has recently been published, and orthologues of genes involved in nervous system development manually annotated. Interestingly, Strigamia retains many genes characterised in vertebrates but lost from other arthropods, including transcription factors involved in CNS development (e.g. Vax, Dmbx).

The anterior medial region of this centipede brain contains a population of very early differentiating neurons that pioneer the longitudinal connectives of the central nervous system. These cells express collier but not achaete-scute homologues, suggesting that they are not serial homologues of segmental neurons. They are distinct from, but lie medially adjacent to Vsx expressing cells of the pars intercerebralis. They express a suite of transcription factors previously shown to characterise cells of the apical organ in a range of invertebrate phyla, and, like apical organ cells, are neurosecretory, on the basis of pro-hormone convertase expression. These cells appear to be without parallel in the brains of insects, and may represent an ancient cell population that has been largely or entirely lost from some arthropod lineages.

Professor Michael Akam FRS, University of Cambridge, UK

Michael Akam studied Zoology at the University of Cambridge and Drosophila genetics at the University of Oxford. As a postdoc with David Hogness at Stanford, he participated in the first isolation of the developmental control genes now known as Hox genes. Returning to Cambridge in 1982, he showed for the first time that Hox genes are expressed at specific positions along the body axis of animals. He has since worked on many aspects of segment patterning in a range of arthropods. His current interests focus on the genetic basis for morphological diversity, and the evolution of developmental mechanisms.

In 1989, he moved as a founding member to the Wellcome/CRC Institute for Cancer and Developmental Biology in Cambridge. In 1997 he became Director of the University Museum of Zoology, and in 2010, Professor of Zoology and Head of the Department of Zoology. He is a Fellow of Darwin College.

The Cambrian explosion

Professor Graham Budd, Uppsala University, Sweden

Abstract

The origin of animals in the so-called “Cambrian explosion” remains one of the most enduring topics of interest within palaeobiology. Although this evolutionary revolution has been intensively studied, many aspects of it remain unclear, including such basic issues as i) when did it take place? ii) what co-evolutionary changes in the rest of the biota took place? iii) what were the geochemical, physical and tectonic backdrops to the relevant events? and iv) what were the biogeographic aspects of the early animal radiations? These areas of interest can be crudely compressed into the rather unilluminating (and potentially misleading) question of “what caused the Cambrian explosion?” Here I review the earliest fossil record of animals and document the rather slow ecological diversification that is implied by the early fossil record of animals. The implications for early nervous system evolution in the major animal clades are considered in this light, with the conclusion that quite distinct evolutionary pressures probably existed in the different clades. This analysis may help guide investigations of extant nervous systems to uncover patterns of homology and convergence.

Professor Graham Budd, Uppsala University, Sweden

Graham Budd (b. 1968) studied at the University of Cambridge, UK, where he completed a PhD under the supervision of Professor Simon Conway Morris FRS (Cambridge) and Professor John S Peel (Copenhagen) on the topic of exceptionally-preserved Cambrian arthropods from Greenland. Since 1994 he has worked in the Department of Earth Sciences of Uppsala University, Sweden where he is currently professor of evolutionary palaeobiology. Current research interests include the early evolution of animals with particular interest in arthropods, the evolution of complex systems and the evolution of development.

Dr Douglas Erwin, National Museum of Natural History, USA

Doug Erwin is a Senior Scientist and curator in the Department of Paleobiology, National Museum of Natural History. His current research interests address various aspects of evolutionary innovation.

Correspondence in general and homology in particular

Dr Michael T. Ghiselin, California Academy of Sciences, USA

Abstract

‘Homology’ is a theoretical term used in the context of explanatory historical narratives. It is a relation of correspondence, not similarity. Homologies are relations between parts that are parts of larger wholes that are ontological individuals. The basic distinction between ‘homology’ and ‘analogy’ is common versus separate origin. Being individuals, homologies and homologues are not kinds (classes), be it natural or artificial ones.

Convergence and other kinds of homoplasy are evolutionary processes, not relations of correspondence. Synapomorphies are shared attributes, not correspondences. Homologues need not be substances, but can fall under other ontological categories, such as place. Body plans are metaphysical delusions that result from treating supraspecific taxonomic categories as if, like the species, they were so-defined as to make the taxa equivalent. Pre-Darwinian systematics is chronologically, not logically, prior to phylogenetics. Evidence for phylogeny includes laws of nature and is not exhausted by morphology. There are good precedents for redefining terms in the light of scientific revolutions.

Dr Michael T. Ghiselin, California Academy of Sciences, USA

Michael T. Ghiselin, born in 1939, is Senior Research Fellow at the California Academy of Sciences in San Francisco, and Chair of its Center for the History and Philosophy of Science. An evolutionary biologist and Darwin scholar, he is interested in the conceptual foundations of systematic biology, especially the ontological status of species and its implications. A comparative anatomist with special expertise on opisthobranch gastropods, he and his collaborators have discussed the chemical defence of these animals as historical narrative. As a bioeconomist he has contributed to the study of hermaphroditism and other reproductive strategies, and to the study of social behaviour. He is author of The Triumph of the Darwinian Method (1969), The Economy of Nature and the Evolution of Sex (1974) and Metaphysics and the Origin of Species (1997).

More on molecular clocks and nervous system evolution

Dr Gregory Wray, Duke University, USA

Abstract

Time is a critical component in understanding the grand arc of nervous system evolution. When did neurons, circuits, ganglia and brains first appear? Did independent origins of parallel traits, such as compound and cameral eyes, occur at the same time? Over what interval did dramatic transformations, such as the enormous size expansion of the human brain, take place? A rigorous temporal frame of reference allows one to address these and other interesting questions. The fossil record and molecular clocks provide the two primary (yet decidedly imperfect) sources of information available for establishing a temporal framework. Our ability to draw inferences from molecular data in particular has increased enormously during the past decade, producing more accurate estimates of some problematic but key divergence times. Combining this information with recent advances in genetics, molecular biology, and phylogenetic relationships can provide important insights into nervous system evolution. This approach will be illustrated at the broad scale of metazoan evolution and the rather narrower scale of human origins.

Dr Gregory Wray, Duke University, USA

Dr Gregory Wray is Professor of Biology at Duke University and Director of Duke’s Center for Genomic and Computational Biology. His research focuses on the evolution of gene regulation. A major topic of interest is the evolution of diet and cognition during human origins, which he studies using a combination of molecular, genetic, genomic, and computational approaches. Current work is aimed at identifying and validating regulatory mutations that altered neural development to produce the unique anatomical features of the human brain. He is also investigating regulatory mutations that altered metabolic processes to support the much larger brain of humans. Greg received his bachelor’s degree from the College of William and Mary and his doctorate from Duke University, after which he carried out post-doctoral research at Indiana University and the University of Washington.

The evolution of neurons and synapses: step-wise emergence of neural modules

Dr Detlev Arendt, European Molecular Biology Laboratory, Germany

Abstract

The first neuron originated early in animal evolution and a plethora of neural cell types emerged since then in the diverging animal lineages. The aim of our laboratory is to track the genealogy of sister cell types in nervous system evolution, to understand the step-wise rise of complexity in sensory-motor circuits.

To this aim, we study and compare the neural modules of cell types in several slow-evolving metazoans. Our approach is to generate cellular maps for several important stages of neurodevelopment, to track the developmental lineages of neuronal differentiation in each system. This involves a combination of in vivo cell lineaging, stage-specific expression atlases, connectivity mapping and single-cell RNA seq approaches.

I will present and discuss recent insight into several key steps of neural cell type origins and diversification in animal evolution, such as the emergence of mechanosensory, chemosensory and photosensory cells from ancient choanocyte-like precursors, the diversification of the first true neurons with synapses, and the specialisation of ciliary and contractile effector cells. These processes involved changes in the composition of cellular modules, such as the sensory apparatus, pre-and post-synapse or ion channels.

Dr Detlev Arendt, European Molecular Biology Laboratory, Germany

Detlev Arendt studied Biology at the University of Freiburg, Germany. In 1994, he revived the classical concept that vertebrates inverted their dorsoventral axis during their evolution. He obtained his PhD in zoology in 1998 from the University of Freiburg, where he compared nervous system development of bilaterian animals. In 1999, he joined the lab of Joachim Wittbrodt at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany, where he worked on eye development. After 3 years of postdoctoral training, he set up his laboratory at the EMBL in 2003 as a Group Leader in the Developmental Biology Unit. The Arendt laboratory has established the marine annelid Platynereis dumerilii, a slow-evolving species, as a new marine molecular model for evolutionary and neurobiological research. The lab has also pioneered the comparison of cell types as a novel approach in the field of evolutionary developmental biology. Major achievements include the identification of vertebrate-type ciliary photoreceptors and of a hypothalamus-like territory in the annelid brain. Also, the Arendt laboratory elucidated an ancient nervous circuit driving phototaxis of the annelid larvae. In 2007, Detlev Arendt became a Senior Scientist at the EMBL and was awarded an honorary professorship at the University of Heidelberg, Germany. In 2012, he was awarded an Advanced Grant by the European Research Council.

Professor Simon Conway Morris FRS, University of Cambridge, UK

Simon Conway Morris is a Professor of Evolutionary Palaeobiology in the University of Cambridge and a Fellow of St John's College. He is best known for his work on the Cambrian explosion (summarised in The Crucible of Creation) and evolutionary convergence (reported in Life's Solution and more recently The Runes of Evolution, as well as the website Map of Life). Current projects involve a new website on evolution (FortyTwo).

Orthologous genes shape convergent nervous system architectures: the case of brachiopods and nemerteans

Dr Andreas Hejnol, University of Bergen, Norway

Abstract

The evolution of nervous system centralisations into brains and neurite bundles is a hotly debated topic in zoology. Recent molecular studies of nervous system architectures in different animal groups ignited the debate anew, and opposing views have been outlined in a number of review articles. The comparison of the molecular patterning systems indicates a high conservation of the underlying molecular networks. One of the involved systems is the medio-lateral patterning set of transcription factors which has been taken as an argument to homologise the centralised nervous systems and cell types within. Based on similarity, it has been proposed that the protostome-deuterostome ancestor had a ventral, centralised nervous system that later disintegrated in several animal lineages. However, major studies have been conducted in groups that possess such a ventrally centralised nervous system – arthropods and annelids – while protostomes with a different architecture have been largely neglected. To investigate the role of the conserved medio-lateral patterning system in animals that lack a ventral centralised nervous system, we have expanded our studies to brachiopods and nemerteans. We tested the hypotheses that the patterning system is lost, re-arranged or involved in other processes than medio-lateral patterning. Our results show differences between brachiopods and nemerteans which raises fundamental questions about evolutionary rearrangements of nervous system architectures and their underlying patterning systems. We emphasise that the direction of evolution can only be detected on the base of a phylogenetic framework and discuss our results based on recent insights into animal relationships.

Dr Andreas Hejnol, University of Bergen, Norway

Andreas Hejnol is research group leader at the Sars International Centre for Marine Molecular Biology in Bergen, Norway. After obtaining his PhD in Comparative Zoology from the Free University Berlin, Germany in 2002 he worked as a postdoctoral fellow in the laboratory of Ralf Schnabel in Braunschweig and at the Kewalo Marine Laboratory in the lab of Mark Q. Martindale in Hawaii. He started his research group “Comparative Developmental Biology” at the Sars Centre in 2009. His current research interest is descriptive, experimental molecular developmental biology of a broad range of invertebrates and includes comparative genomic approaches and phylogenomics. The main research goal of which is to understand the evolutionary origin and diversification of animal body plans.

Homologous or convergent nervous system evolution: the dirty laundry

Professor Nicholas Holland, Scripps Research Institute, La Jolla, USA

Abstract

At present, considerations of nervous system evolution are beset by several general problems that arise in any discussion of long-range evolution (at the level of one phylum to the next). First, genotype/phenotype relationships are poorly understood. Indeed it is still being discussed whether rewiring gene networks leads to morphological change or vice versa. Second is the difficulty in making body part homologies between animals with markedly diverse overall morphologies. Third, and strongly impacting the foregoing, is the instability of key parts of contemporary trees of animal phylogeny. Fourth, is the difficulty of deciding whether absent characters have never existed or have secondarily disappeared. In addition, when discussing nervous system evolution, there are particular semantic questions that arise: for instance, what degree of centralisation should define a central nervous system and what degree of braininess constitutes a brain. None of these problems can be solved at a stroke. Instead, progress will depend on amassing an abundance of reliable information over the whole spectrum of animal phyla and on a more standardised and effective use of language in neurobiology.

Professor Nicholas Holland, Scripps Research Institute, La Jolla, USA

Nicholas D. Holland received his BA from Carleton College (Northfield, Minnesota) in 1960 and his doctorate in biology from Stanford University in California in 1964. After two years in Italy at Stazione Zoologica di Napoli as a postdoctoral fellow, he returned to California to take an assistant professorship in the Marine Biology Research Division at the Scripps Institution of Oceanography, University of California at San Diego (UCSD). He was later promoted to Associate Professor (1972) and then to Professor (1978) of marine biology at the same institution. He was appointed Distinguished UCSD Professor in 2008. His research interests include considering how vertebrates evolved from invertebrates. He has worked with cephalochordates. In particular, he is interested in body part homologies between distantly related animals, suggested through comparative molecular genetics.

Brain evolution of language and dance

Abstract

Understanding the evolution and mechanisms of how brain pathways for complex behaviours evolve has been mysterious. One such trait is vocal learning, which is critical for song in song-learning birds and spoken language in humans. Vocal learners have forebrain to brainstem vocal control systems, whereas vocal non-learners only have brainstem vocal systems. We found that the specialised song learning systems of song-learning birds (songbirds, parrots, hummingbirds) are embedded within an ancient vertebrate motor system involved in limb and body movements. The song learning and adjacent motor systems share many features in common, including motor-driven gene expression cascades, and an anterior pathway necessary for motor learning and a posterior pathway necessary for movement production. However, comparative anatomical molecular analyses show specialised convergence of the vocal pathways in these birds with those for spoken language in humans. To explain these findings, I propose a motor theory for the origin of vocal learning, where ancient brain systems used to control movement and motor learning gave rise to brain systems to learn and produce song and spoken language. The new motor system is connected to muscles of the vocal organ to control a specialized form of learned movement control – song and speech, which has specialised changes in genes involved in neural connectivity and neural activity. The auditory-motor connectivity of the vocal learning system in turn influences the adjacent motor system to allow vocal learners to synchronise their body movements to rhythms in sounds heard, that is, learning to dance. In this manner, the evolution of brain pathways for vocal learning may have evolved independently of a common ancestor, but dependent on a pre-existing motor learning pathway scaffold that then diverged.

Dr Erich Jarvis is an Associate Professor of Neurobiology and Howard Hughes Medical Institute (HHMI) Investigator at the Institute for Brain Sciences at Duke University School of Medicine. Since turning down an audition with the Alvin Ailey Dance Theater to pursue science, Erich Jarvis has studied molecular pathways in avian brains as a window into how the brain controls complex behaviour. He has proposed theories about the evolution of vocal production and learning in birds and how it relates to the origins of human language. A graduate of Hunter College, Jarvis conducted research in bacterial molecular genetics with Rivka Rudner. He later earned his PhD in molecular neurobiology and animal behaviour in 1995 at the Rockefeller University, where he did graduate and postdoctoral work in the lab of Fernando Nottebohm. Using a method he termed "behavioural molecular mapping" to determine how a bird's motor activities influence the resulting changes in gene expression in the brain, Jarvis has traced out the brain pathways for vocal learning in three distantly related birds—parrots, hummingbirds, and songbirds—and is now exploring evolutionary connections to understand how these pathways develop. Awards for his work include the NSF’s Alan T. Waterman Award, the NIH Director’s Pioneer Award; his work made Discover's top 100 science discoveries of 2005, and he was chosen one of Popular Science’s Brilliant 10 of 2006.

Xenacoelomorpha, a tale of nervous system centralisation?

Professor Pedro Martínez, Universitat de Barcelona, Spain

Abstract

Xenacoelomorpha is, most probably, a monophyletic group that includes three clades: Acoela, Nemertodermatida and Xenoturbellida. The group still has contentious phylogenetic affinities; though most authors place it as the sister group of the remaining bilaterians, some would include it as a fourth phylum within the Deuterostomia. Over the last few years, our group, along with others, has undertaken a systematic study of the microscopic anatomy of these worms; our main aim is to understand the structure and development of the nervous system. This research plan has been aided by the use of molecular/developmental tools, the most important of which has been the sequencing of the complete genomes and transcriptomes of different members of these clades. The data obtained has been used to analyse the evolutionary history of some gene families and to study their expression patterns during development, in both space and time. A major focus of our research is the origin of "cephalised" (centralised) nervous systems. How complex brains are assembled from simpler neuronal arrays has been a matter of intense debate for at least a hundred years. We are now tackling this issue using Xenacoelomorpha models. These represent an ideal system for this work, since the members of the three clades have nervous systems showing different degrees of cephalisation; from the relatively simple sub-epithelial net of Xenoturbella to the compact brain of acoels. How this process of "progressive" cephalisation is reflected in the genomes or transcriptomes of these three groups of animals is the subject of my presentation.

Professor Pedro Martínez, Universitat de Barcelona, Spain

Pedro Martínez graduated in Chemistry (Biochemistry and Molecular Biology) in 1982 from the Universitat Autònoma de Barcelona, where he also obtained his PhD in 1990. Martínez completed his training in several places, but mainly at the California Institute of Technology (Pasadena, USA) and at the Centro Nacional de Biotecnología (Madrid, Spain). Before his ICREA appointment, Martínez was Associate Professor in the Faculty of Medicine at the University of Bergen (Norway). Currently Martínez is an ICREA Research Professor at the Universitat de Barcelona, Departament de Genètica, a position that he has held since 2003. Martínez’s research focuses on the evolution of developmental mechanisms. At the Universitat de Barcelona he is also head of the genetics doctoral programme.

Homology or convergence of neurogenesis?

Professor Brigitte Galliot, University of Geneva, Switzerland

Abstract

Phenotypic traits derive from the selective recruitment of genetic materials over macro-evolutionary times, and protein-coding genes constitute an essential component of these materials. The mechanisms that drive innovations roughly distribute between homology, parallelism or convergence. Indeed a number of recent molecular analyses of cellular innovations point to “mixed” processes where homologous molecular tools are independently recruited for similar cellular processes. To investigate the mechanisms driving such mixed evolutionary events, we analysed the recent production of genomic scale data from sponges and cnidarians, sister groups from eumetazoans and bilaterians, respectively, to date the emergence of human proteins and to infer the timing of acquisition of novel traits through metazoan evolution. That way we identified a premetazoan proteome that associates with 43% of all annotated human biological processes, and four major waves of innovations inferred in the last common ancestors of eumetazoans, bilaterians, euteleostomi and hominidae. Interestingly, groups of proteins that act together in their modern human functions often originated concomitantly, although the corresponding human phenotypes frequently emerged later. We take the example of three cnidarians, Acropora, Nematostella, and Hydra that express a highly similar protein inventory to show that innovations are affiliated either to traits shared by all eumetazoans (gut differentiation, neurogenesis), or to bilaterian traits present in only some cnidarians (eyes, striated muscle), or to traits not identified yet in this phylum (mesodermal layer, endocrine glands). The variable correspondence between phenotypes predicted from protein enrichments and observed phenotypes suggests that a parallel mechanism repeatedly produce similar phenotypes. We propose that novel regulatory events independently tie preexisting conserved genetic modules.

Professor Brigitte Galliot, University of Geneva, Switzerland

Brigitte Galliot, MD, PhD, is Associate Professor at the Department of Genetics and Evolution, and Vice-Dean of the Faculty of Sciences, University of Geneva, Switzerland. Her research interest focuses on the identification of the molecular and cellular mechanisms that allow an adult organism to reactivate its developmental programmes(s) after injury or amputation, including de novo neurogenesis. For this, she is using the freshwater cnidarian Hydra polyp as model system. Indeed Hydra can regenerate any missing part of its body after bisection, including its apical nervous system. Basic principles of animal regeneration might be uncovered in this simple animal, as for example the driving force played by injury-induced cell death.

Synapse evolution: the vertebrate expansion in complexity

Professor Seth Grant, University of Edinburgh, UK

Abstract

Synapses are a defining feature of the nervous system. Over the last decade, proteomic studies have generated comprehensive descriptions of their protein components. Comparison of mouse and fly synapse proteomes revealed increased complexity in vertebrates, which was secondary to two rounds of genome duplication. In addition to comparative studies of synapse proteome complexity in fly, mouse, fish and human we have developed experimental approaches that probe the functional importance of this complexity. Using genetic modification of paralogs in important synaptic proteins, we have identified conserved and derived features in the mammalian behavioural repertoire. Behavioural and electrophysiological studies show increased functional complexity. We are developing methods to examine synapse diversity by mapping molecules in individual synapses and preliminary data shows synapse proteome complexity generates synapse diversity. Biochemical studies of protein complexes shows the multiplicative ‘combinatorial explosion’ that follows duplications was highly constrained by vertebrate-specific genetic rules. Together these findings indicate that synapse proteome complexity and genome evolution shaped the structure and function of the vertebrate nervous system.

Professor Seth Grant, University of Edinburgh, UK

Seth Grant graduated from Sydney University with a Bachelor of Science (Medicine) in Physiology, Bachelor of Medicine and Bachelor of Surgery. From 1985-1989 he was a Postdoctoral Fellow at Cold Spring Harbor Laboratory with Douglas Hanahan studying transgenic mouse models of cancer. From 1989-94 he studied mouse genetic models of learning and memory with Eric Kandel at Columbia University. He established his laboratory at the Centre for Genome Research at Edinburgh University in 1994 and in 2000 was appointed Professor of Molecular Neuroscience. In 2003 he was appointed Principal Investigator at the Wellcome Trust Sanger Institute in Cambridge and remained there until 2011, when he returned to Edinburgh University. He has held additional appointments including the John Cade Visiting Professor at Melbourne University, Honorary Professorship at Cambridge University and elected Fellow of the Royal Society of Edinburgh. His work focuses on the molecular basis of synapse function and behaviour. He has characterised synaptic proteome organisation, evolution and function and identified the key role played by supramolecular assemblies of postsynaptic proteins. His synapse proteomic and genetic work has lead to the identification of many diseases impacting on the synapse and the multiprotein complexes that control cognition.

Evolutionary conserved mechanisms for the selection and maintenance of behavioural actions

Dr Frank Hirth, King's College London, UK

Abstract

The coordination of adaptive behaviour is a prerequisite for survival and reproduction. Its development and manifestation must be a reliable event for species where strong selection pressure is imposed on effective sensorimotor transformation and action selection. Accordingly, adaptive behaviour can be described as a phylogenetically acquired activity that depends on the physiological function of central nervous system sub-structures. Lorenz and Tinbergen already postulated that the heritable ontogeny and reliable performance of these CNS structures relies on a genetically-determined programme, referred to as a ground pattern. In this talk I will discuss three emerging principles underlying the evolutionary conserved ground pattern formation of the insect central complex and vertebrate basal ganglia, namely clonal unit architecture, temporal identity and functional compartmentalisation. I will present evidence that the basal ganglia and central complex regulate homologous functions in the coordination and control of adaptive behaviour. Using the Drosophila central complex as a paradigmatic example, I will illustrate the neural mechanisms and computational logic underlying the selection and maintenance of behavioural actions, and how these can be applied to understand human basal ganglia and their related disorders, including Parkinsons's disease.

Supported by the UK Medical Research Council, the Royal Society, the Wellcome Trust, and the Air Force Research Laboratory.

Dr Frank Hirth, King's College London, UK

Frank Hirth is a senior lecturer and principal investigator at the Institute of Psychiatry, Psychology and Neuroscience (IoPPN) at King's College London. He received his PhD in Zoology at the University of Basel in Switzerland and trained in neurogenetics at the universities of Freiburg, Basel and the MRC National Institute of Medical Research in London. During his time at the Institute of Zoology in Basel, he discovered evolutionary conserved genetic mechanisms underlying pattern formation in the insect and mammalian brain. His current research focuses on neural mechanisms underlying action selection in health and disease, and their evolutionary conservation.

Abstract

Retinal projections in amniotic vertebrates terminate in six major central targets and, though less extensively studied, in anamniotes as well. Though the macroarchitecture may present dramatic differences in appearance, the functions of each of these homologous target systems is highly conserved, and analysis of the microcircuitry, function, molecular properties and gene expression in mammals and reptiles/birds within each of these subsystems has uncovered a remarkable degree of conservation across phylogeny. These studies strongly suggest that the fundamental algorithms that mediate complex operations remain embedded in highly conserved homologous circuitry at all levels of the brain, including those for stereopsis, high speed motion detection, pupillary control, oculomotor control, vestibulo-ocular reflexes, circadian control, and perhaps even higher visual cognitive functions. Speculations regarding the localisation of particular functions of the optic tectum being "taken over" by the striate cortex do not appear justified. Many of the interpretations of seemingly major evolutionary changes reflect the paucity of data, rather than evidence of novelty in different clades. When, where and how in the genome these highly conserved pathways and microcircuits were first established, preserved and expressed is unknown.

Dr Joseph Ryan, University of Florida, USA

Joseph Ryan is Assistant Professor of Biology at the Whitney Laboratory for Marine Bioscience (University of Florida) in the United States. His research concentrates on the evolution of animal genomes with a particular focus on how changes in animal genomes have influenced developmental processes over time. He has an AA in general studies from Essex Community College in Baltimore, a BS in Computer Science from the University of Maryland University College, and a PhD in Bioinformatics from Boston University. He did a postdoc at the National Human Genome Research Institute and at the Sars Centre for Marine Molecular Biology before starting his present position in 2014.

A multitude of similarities and minuteness of resemblance: do ground patterns of forebrain organisation support genealogical correspondence of brains across phyla?

Gabriella Wolff, University of Arizona, USA

Abstract

A common tripartite organisation of the deuterostome and protostome brain is implied from fossil evidence and from functional equivalence of homologous genes that are cardinal to brain segmentation. However, correspondence of brain segmentation is insufficient to claim common ancestry of arthropod and chordate forebrains unless correspondence can be further identified with respect to neural circuits. This talk will demonstrate examples of corresponding neural arrangements of brain centres, which in arthropods and chordates, underlie action selection and allocentric memory. The ground pattern organisation of these centres, defined by their neuroanatomical organisation and homologous protein expression patterns, are common to four invertebrate phyla belonging to Ecdysozoa and Lophotrochozoa. Corresponding organisations are also found in the forebrains of chordates. We propose that the most parsimonious explanation for such correspondences is that they derive from common ancestral ground patterns rather than from convergent evolution of similarities. It is proposed that an ancient origin of two ground patterns, one for mediating place memory the other for behavioural choice, implies a one-time appearance of a brain in the last common ancestor of protostomes and deuterostomes.

Gabriella Wolff, University of Arizona, USA

Gabriella Wolff received a BSc Molecular and Cellular Biology and a BA in French, and is currently a PhD student in the laboratory of Professor Nicholas Strausfeld at the University of Arizona, Department of Neuroscience. She is a fellow of the National Science Foundation Graduate Research Fellowship Program, a PEO Scholar and is currently serving on the Council of the International Society for Neuroethology as an early-career member. The focus of her dissertation work is seeking to elucidate the evolutionary origin of forebrain structures through comparative neuroanatomical and protein expression studies. In April 2015, she will defend her dissertation on “Genealogical correspondence of learning and memory centers across phyla”.

Have microbes influenced the evolution of nervous system and behaviour?

Dr Heather Eisthen, Michigan State University, USA

Abstract

Animals ubiquitously interact with environmental and symbiotic microbes, and the effects of these interactions on animal physiology are currently the subject of intense interest. Nevertheless, the influence of microbes on nervous system evolution has been largely ignored. In this talk, I will explain how taking microbes into account might enrich our ideas about the evolution of nervous systems. For example, microbes are believed to have contributed to the evolution of neurotransmitters through lateral gene transfer to animal hosts, and their involvement in animals’ defensive, communicative and dispersal behaviours have likely influenced the evolution of chemo- and photosensory systems in animals. Our own work suggests that amphibians have co-opted metabolites of their skin microbes, as well as their own antimicrobial peptides, for use as chemical signals. These events have required adaptations by the host’s nervous system. Our primary study subject, the rough-skinned newt (Taricha granulosa) is an intriguing example. Its potent defensive neurotoxin (TTX) is most likely a microbial metabolite, and TTX appears to secondarily function as a chemical signal for the newt. If so, newts likely evolved novel mechanisms for chemosensory detection of TTX in addition to having evolved TTX-resistant ion channels. We hope that our work with newts and other amphibians will provide a new model system for understanding the neural and behavioural consequences of animals evolving in a microbial world.

Dr Heather Eisthen, Michigan State University, USA

Heather Eisthen began her research career at the Monell Chemical Senses Center while an undergraduate student at the University of Pennsylvania. She earned a PhD at Indiana University, participating in their Center for the Interdisciplinary Study of Animal Behavior. Two postdocs followed – one at University of California, San Diego with Glenn Northcutt and a second at the Marine Biological Laboratory in Woods Hole with Vince Dionne. She has been on the faculty at Michigan State University since 1997, where her research has centred on the evolution of olfactory systems and pheromonal communication in vertebrates, particularly amphibians.

Evolution of brain elaboration

Dr Sarah Farris, West Virginia University, USA

Abstract

Large, complex brains have evolved independently in several lineages of protostomes and deuterostomes. While sensory centres in the brain increase in size and complexity in proportion to the importance of a particular sensory modality, the selective pressure driving enlargement of higher, integrative brain centres has been more difficult to determine. The capacity for flexible, innovative behaviours, including learning and memory and other cognitive abilities, is most commonly observed in animals with large higher brain centres. Other factors, such as social grouping and interaction, appear to be important in a more limited range of taxa. Regardless of the adaptive and behavioural significance, evolutionary increases in brain size tend to derive from common modifications in development, and generate common architectural features, even when comparing widely divergent groups such as vertebrates and insects. These similarities may be in part due to deep homology of the brains of all Bilateria, in which shared patterns of developmental gene expression give rise to positionally, and perhaps functionally, homologous domains. Other shared modifications of development appear to be the result of convergence, such as the repeated, independent expansion of neuroblast numbers through changes in genes involved in mitotic spindle orientation. The common features of large brains in so many groups of animals suggests that whether by homology, convergence or constraint, there are a limited set of mechanisms for increasing structural and functional diversity in bilaterian nervous systems.

Dr Sarah Farris, West Virginia University, USA

Sarah Farris grew up in the rural Midwestern United States and cultivated an interest in insect morphology and behaviour from a young age. She acquired a B.S. degree in Biology at the University of Iowa, and M.S. and PhD degrees in Entomology at the University of Illinois at Urbana-Champaign. Her dissertation research with Dr Susan Fahrbach and Dr Gene Robinson focused on the anatomy and development of an insect higher brain centre, the mushroom bodies, in the honey bee Apis mellifera. Her postdoctoral work with Professor Nicholas Strausfeld at the University of Arizona introduced her to comparative studies of insect brain development and neuroarchitecture, which have remained the focus of her research as a faculty member at West Virginia University.

Dr Linda Z. Holland, Scripps Research Institute, La Jolla, USA

Linda Z. Holland received BA and MA degrees in biology from Stanford University, Palo Alto, CA, USA and a PhD from the University of California San Diego (UCSD), La Jolla, CA, USA. She began her scientific career as an ecological physiologist studying proteins during reproductive cycles of echinoids, and went on to study regeneration in echinoids and the electrical polyspermy block and oogenesis in the marine worm Urechis caupo. After working as a biochemist studying protein-protein interactions in human blood clotting and identifying amino acids in lactate dehydrogenases responsible for fine-tuning enzyme kinetics, she returned to developmental biology. During 1986/87 at the Station Zoologique in Villefranche/mer in France, she studied fertilisation in pelagic tunicates, leading to the proposal that contrary to accepted dogma, appendicularians, not ascidians, are basal in the tunicates, a position later confirmed by molecular phylogenetics. She then moved to UCSD and focused on how vertebrates evolved from their invertebrate ancestors, using amphioxus as a proxy for the ancestral chordate. She led the community effort to sequence the amphioxus (Branchiostoma) genome and has recently been studying the second genus of amphioxus (Asymmetron). This work has shown that amphioxus species are evolving more slowly than the slowest-evolving vertebrate known. To date, she has 172 publications.

Abstract

Invertebrate central pattern generator (CPG) circuits provide a unique opportunity to study the evolution of behaviour and neural circuits. CPGs are neural circuits that produce the pattern of neural activity that underlies rhythmic motor behaviours such as walking, swimming, and feeding. The detailed neuronal circuitry of several invertebrate CPGs have been determined. Comparing the roles of homologous neurons in the generation of rhythmic motor patterns provides an unambiguous means to assess the relationship between homology and function in the evolution of behaviour. This has been explicitly studied in the swimming behaviours of the Nudipleura (Mollusca, Gastropoda, Heterobranchia). Phylogenetic evidence suggests that swimming behaviours evolved independently several times within this monophyletic clade. Furthermore, there are two categorically different forms of swimming, dorsal – ventral (DV) and left – right (LR) body flexions. The CPGs for DV and LR swimming differ in the composition of neurons, yet the brains of those species contain homologs of the CPG components for both types of behaviour. Thus, in species with categorically different behaviours, homologous neurons have different functions. Parallel evolution of neuromodulation may be a mechanism for independent evolution of behaviour; serotonergic neuromodulatory mechanisms, critical for DV swimming, are absent in a LR swimmer. Even in species with analogous behaviour, homologous neurons can have different functions; two LR swimming species have only partial overlap in the neurons that compose the CPG. Furthermore, the roles of homologous CPG neurons and their activity patterns during the behaviour differ, thus the neural mechanisms underlying analogous behaviours differ. These results are consistent with the notion of different hierarchical levels of biological organisation. Behaviour arises from the neural circuits, but several configurations of neural circuitry can give rise to the same behaviour and different behaviours can arise from brains with the same set of neurons.

Dr Paul Katz, Georgia State University, USA

Paul S Katz graduated from Northwestern University in 1982 and received his PhD in 1989 from Cornell University, where he worked on the stomatogastric ganglion of crabs in the laboratory of Dr Ronald Harris-Warrick. He began his work on nudibranchs as a Research Assistant Professor at the University of Texas Health Science Center in Houston in collaboration with Dr William Frost. He moved to Georgia State University in 1997, where he is currently a Distinguished University Professor in the Neuroscience Institute. He served as Co-director for the Neural Systems and Behavior course at the Marine Biological Lab in Woods Hole, MA, as Associate Editor for the Journal of Neurophysiology, and as President of the International Society for Neuroethology. Dr Katz uses sea slugs (Mollusca, Gastropoda, Nudipleura) to study the evolution and operation of central pattern generators that control swimming behaviour.

Convergent evolution of nervous systems and synapses in ctenophores

Professor Leonid Moroz, University of Florida, USA

Abstract

Using advanced sequencing and microanalytical technologies, we investigated the distribution of canonical ‘synaptic and neuronal machinery” among ctenophores, sponges, placozoans and cnidarian/bilateria clade. Results of this analysis lead us to propose an alternative hypothesis that not only have neurons evolved in parallel, but also synapses. Ctenophores, or comb jellies, represent an example of convergent evolution of neural systems uniquely developed to control complex cilia-based life-styles and behaviours. First, novel genome-wide analyses place ctenophores as a sister group to other animals. Second, ten ctenophore species we investigated so far have a smaller complement of pan-animal genes controlling canonical neurogenic, synaptic, muscle and immune systems, and developmental pathways than most other metazoans. However, comb jellies are carnivorous marine animals with a complex neuromuscular organisation and sophisticated patterns of behaviour. To sustain these functions, they have evolved a number of unique molecular innovations supporting the hypothesis of massive homoplasies in the organisation of integrative and locomotory systems. Third, many bilaterian/cnidarian neuron-specific genes and 'classical' neurotransmitter pathways are either absent or, if present, not expressed in ctenophore neurons (e.g. the bilaterian/cnidarian neurotransmitter, γ-amino butyric acid or GABA, is localised in muscles and presumed bilaterian neuron-specific RNA-binding protein Elav is found in non-neuronal cells). Surprisingly, we found that most of these ‘synaptic’ genes are being expressed before neurons ever appear in development suggesting that this secretory machinery is commonly recruited for a diversity of non-neuronal functions and cannot be used as neuronal/synaptic markers per se. Another evidence for convergent evolution of intercellular signalling presents our molecular analysis of regeneration and neurogenesis in ctenophores. Finally, metabolomic and pharmacological data failed to detect either the presence or any physiological action of serotonin, dopamine, noradrenaline, adrenaline, octopamine, acetylcholine or histamine - consistent with the hypothesis that ctenophore neural systems evolved independently from those in other animals. Glutamate and a diverse range of secretory peptides are first candidates for ctenophore neurotransmitters. Nevertheless, it is expected that other classes of signal and neurogenic molecules would be discovered in ctenophores as the next step to decipher one of the most distinct types of neural organisation in the animal kingdom.

Professor Leonid Moroz, University of Florida, USA

Moroz earned his PhD in comparative physiology from the Institute of Developmental Biology in Moscow (1989). He was an international HHMI scholar. His postdoctoral research was done with Dr William Winlow at the University of Leeds, UK and with Dr Rhanor Gillette at the University of Illinois, Urbana, USA. He joined University of Florida in 1998.

Brain & Memory Genomics: Moroz’s laboratory focuses on the mechanisms underlying the design of nervous systems and develops innovative approaches to study the genomic basis of neuronal identity and plasticity. His team pursues understanding what makes a neuron a neuron and why they differ so from each other; how they maintain such precise connections between each other; how this fixed wiring results in such enormous neuronal plasticity; and how this contributes to learning, memory mechanisms, aging and regeneration.

Ocean & Space Genomics: The second groups of projects deal with exploration of life frontiers and evolution. Here, Moroz’s lab is focusing on global biodiversity targeting little/under investigated lineages of animals (e.g. sequencing genomes of ctenophores) and their adaptation to extreme environments from cold Antarctic to Space. Moroz has performed a number of oceanic expeditions across the globe (his sequencing-on-ship, Ship-Seq, attracted world-wide attention) and collaborated with NASA and Russian Space Programs to study adaptations to microgravity including orbit missions.

Moroz’s work has been published and covered widely with more than 130 papers including Nature, Science, Cell, Neuron, PNAS, etc.

Convergent evolution of brains and minds?

Professor Gerhard Roth, University of Bremen, Germany

Abstract

While all animals including protozoans reveal simple forms of learning (habituation, sensitisation, classical conditioning and often operant conditioning), “higher” cognitive abilities, such as tool use and fabrication, imitation, insight, reasoning and sometimes mirror self-recognition (often called “mind” or “intelligence”), have been demonstrated only in a few groups, often belonging to distantly related taxa, e.g. social insects, cephalopods, birds and primates. While in all of these cases, an increase in absolute and/or relative brain size can be observed, the best correlation between the degree of intelligence and brain features within “intelligence centres” concerns (i) the number of neurons, (ii) packing density and interneuronal distance, (iii) axonal conduction velocity, and (iv) a specific neural architecture of the “intelligence centres” as a densely connected associative network. If these “intelligence centres” (mushroom bodies, vertical lobe, nidopallium, associative cortex) have evolved independently, then the great similarity among these features is an excellent example of the convergent evolution of high general information processing abilities. This insight enables us to explain, why animals with very large brains (elephants, dolphins, whales) reveal only moderate intelligence, because of large interneuronal distance and low axonal conduction velocity. In some cases like honeybees, songbirds, mammals/primates including Homo sapiens the presence of a complex language has served as an additional “intelligence amplifier” and become the basis of culture and individual knowledge transfer.

Professor Gerhard Roth, University of Bremen, Germany

Roth was born 1942 in Marburg (Germany). Roth’s education and degrees include: 1963-1969 study of Philosophy, German Literature and Musicology at the Universities of Muenster (Germany) and Rome (Italy). 1969 PhD in Philosophy at the University of Muenster. 1969-1974 study of Biology at the University of Muenster and University of California, Berkeley. 1974 PhD in Zoology at the University of Muenster. Since 1976 Roth has been Professor of Neurobiology (Chair of Behavioral Physiology and Developmental Neurobiology) at the University of Bremen. From 1988-2008 he was Director of the Brain Research Institute at the University of Bremen; and from 1997-2008 Founding Rector of the Hanse Institute for Advanced Study Delmenhorst. 2003-2011 Roth was President of German National Academic Foundation (Studienstiftung des deutschen Volkes). Since 2008 he has been CEO of Roth GmbH – Applied Neuroscience (Bremen). Roth has written around 220 scientific articles in neurobiology and neurophilosophy, including 12 books.